We broke away from singapore after we used it -- I can't remember what we used for 7th grade math (it was a like a review before pre algebra) for for pre-algebra we used Teaching textbooks. http://teachingtextbooks.com/ My ds did not love it, and we had used the Keys to . .. program in the past to supplement singapore, so we are using Keys to Algebra with some extras this year with great success. http://www.keypress.com/x6469.xml
